The present invention relates to an improved auxiliary equipment enclosure unit for detachable mounting at either ring or ringless types of watthour meter sockets.
Equipment enclosure units having an interposed mounting between a detachable watthour meter and a standard watthour meter socket are known for installation of auxiliary equipment at an existing electric energy metering installation. The standard meter sockets include two conventional types referred to as the ring and ringless types. The detachable meter sockets generally include an enclosure, which sometimes takes the form of a meter box, and female or jaw type terminals for receiving blade or bayonet type terminals extending from watthour meters having standard detachable mounting arrangements. When installing a detachable meter at a ring type socket, a conventional sealing ring having a split circular configuration and a U-shaped cross section is used. The sealing ring holds the periphery of a standard meter base arrangement used in detachable watthour meters, against an outer extending radial mounting rim of the ring type socket. The ends of the sealing ring are locked in a contracted position for clamping the watthour meter on the ring socket, as is well known. When installing a detachable meter at a ringless type socket which includes a box enclosure, a front cover of the enclosure is opened so that a circular opening thereof can receive the front of the meter. When the cover is closed, the edges of the cover opening prevent the meter from being removed from the meter socket enclosure. The above detachable meter mounting arrangements are often desired to accommodate mounting of an auxiliary equipment enclosure unit as well as detachable watthour meters at either type of meter socket.
When auxiliary or supplementary metering and distribution line control equipment or circuits are to be removably installed at standard detachable watthour meter sockets, the associated enclosure units are desired to have a number of characteristics. The enclosure units are to carry and protect different auxiliary equipment or circuits which may be larger than the diameter of a detachable meter; be capable of having the rear end thereof easily and simply attached to either of the two types of ring and ringless meter sockets; be capable of having a detachable watthour meter attached at a front end, thereof, if desired; be capable of maintaining the standard metering connections between the meter and the socket terminals when a detachable meter is mounted thereto; be made in a simple and low cost manner; and be useable without alteration or modification of the detachable mounting arrangements of either the meter socket or the meter.
In U.S. Pat. No. 4,121,147 an auxiliary housing has an open front which carries a standard watthour meter and further includes auxiliary jaw terminals receiving the meter blade terminals. The rear of the auxiliary housing has an outer circular rim substantially the same diameter as the rear mounting flange of the base of a standard watthour meter. Auxiliary blade terminals are provided at the housing rear for insertion into meter socket terminals. An auxiliary housing or enclosure of the aforementioned type is satisfactory and can be installed at either type of meter socket so long as the outer periphery of the auxiliary housing does not extend radially beyond the rear mounting rim thereof. Often the housing size cannot be so limited and still be satisfactory for carrying larger types of auxiliary equipment. In U.S. Pat. No. 3,714,516 a large auxiliary equipment housing is disclosed for mounting between a detachable watthour meter and either of the ring or ringless types of meter sockets. A separate mounting adapter fastens to the rear of the housing and has two separate diametrically disposed locking members which must be installed with screws. Each locking member has two axially spaced and radially extending fingers to form two diametrical sets of radially extending fingers. The different sets of coplanar fingers provide two relatively small radial extensions for clamping the housing to either the ring or ringless types of meter sockets. An additional set of resiliently biased blade to jaw terminal connections or joints are required in the housing.
Further examples of prior art auxiliary equipment enclosure units are disclosed in U.S. Pat. Nos. 2,606,232; 3,067,362; 3,167,690; 3,334,276; 3,549,951; and 3,643,209 for use with watthour meters and with one but not both types of meter sockets and wherein the enclosure unit has a larger size than the diameter of the meter.